Human desire has evolved as a response to the real needs of our bodies. Desire is natural and should be embraced rather than resisted. To read some evolutionary psychologists, it would seem that nature has programmed desire deeply into our DNA. It appears that we can no more choose our basic appetite for things than we can select our skin color or pick out our parents. Is desire always a natural response? Is it normal and good? Should we give in to our desire? Must we act upon it?

In Milan Kundera’s The Unbearable Lightness of Being, lead character Tomas is a man who believes sex is a natural and inevitable part of life. His impulses lead him to have sex with many women. Although his actions are immoral, he sees in this behavior no compromise in his love for his wife Tereza. To him, sex is just a natural desire that in no way interferes with his marriage.

His wife Tereza, by contrast, feels fatalistically stuck with Tomas, the man she desperately loves. She knows about his womanizing but feels helpless to change either her husband or her life situation in any meaningful way. She is miserable, and her despondency eventually makes Tomas miserable as well. Kundera masterfully portrays both characters as victims of natural, instinctual desires.

My question is whether or not we are helpless victims in a life of uncontrollable desire that leads to intuitive actions and fateful consequences. Are we at our best when we give in to our desire? Or is it possible to make choices that demonstrate our mastery over desire? Can we be free from its tyranny?

The Tenth Commandment states, “You shall not covet.” The intent of this word is to set limits on our desire. There are some things in life you should not want—even if the impulse is automatic. Desire becomes evil when it infringes on the rights of others or when it harms our neighbor. In opposition to what some evolutionary scientists seem to think, God tells us that desire should not always be acted upon. We are not free to do as we choose—or as nature might incline us.

Uncurbed desire does more, however, than just harm our neighbor. It breaks our relationship with God and places us in jeopardy of becoming idolaters. An unchecked appetite prevents gratitude for what we already have, and it blocks the memory of how bad things used to be. Desire opens the door for unhealthy feelings of nostalgia and entitlement, making us want more than we need.

Desire can be good. It can push us to perform well, to expand our skills, and to accomplish things that require extra effort. God made the world good. It’s filled with pleasant things that are delightful to see, touch and taste. Texts such as Song of Songs highlight the inherent beauty of relationships and the passion that accompanies them. This is a good world that God made, and we should enjoy it.

But desire slips from healthy and good to deadly and evil when we fail to control it. In 1 Thes 4:4 Paul writes, “But each of you should learn to control your own body.” Desire is not nature’s beck and call to which we must respond in the affirmative. While there’s no need to live a life of constant self-deprivation just for the sake of self-deprivation, there is also no reason to say yes to every apparent urge and appetite.

A simple life can be more rewarding than a complex life. But being content with simplicity comes by harnessing our desires. In order to properly love our neighbors, we have to appreciate what we already have rather than longing for what they have. As Paul said, “I have learned to be content with whatever I have. I know what it is to have little, and I know what it is to have plenty. In any and all circumstances I have learned the secret of being well-fed and of going hungry, of having plenty and of being in need. I can do all things through him who strengthens me” (Phil 4:11-13).

In The Unbearable Lightness of Being, we see the difficult nature of desire. Tomas and Tereza finally find happiness by leaving the big city and settling in the country. Tereza’s desire to be with her husband is good and right, while Tomas’s desire was destroying his wife, himself, and their marriage. By saying no to a destructive kind of desire and yes to another, more healthy kind, the book affirms what Scripture teaches: desire must be defeated and denied when it has the potential to destroy others. But when desire blesses others, it can lead to fulfillment.

Simply put, desire is dangerous if we don't stop and analyze its impact on others. Natural or not, desire must not be our master. We must learn to harness it for our own good and for the welfare of our neighbors.